Can someone make DEM from these given X,Y,Z data?

Anand

Posted 15 February 2012 - 11:33 PM

Anand

Contributor

Validated Member

15 posts

United Kingdom

Could someone please make a DEM for me from this data given. It's not that large data hope it won't take long for you people. I'm running some 2D simulation on ISIS and need to use the DEM regarding this data given. I don't have any experience on this. By the way, the data in the .txt are only the ground elevation which means Z.
Best regards

Anand

Posted 16 February 2012 - 01:54 PM

pete.wells

Posted 16 February 2012 - 03:56 PM

pete.wells

Newbie

Validated Member

5 posts

United Kingdom

Distance between the points are 1000m on each X,Y direction.

OK... so we have a cell size now. This will be all you'll need to model the area in ISIS 2D, however, the results that ISIS 2D will not be properly georeferenced (as you do not know where the bottom-left corner of the grid is located).

You may also need to convert the spaces between values to a single space (probably best done with a simple python script).

Bear in mind that ISIS 2D will do a nearest neighbour sampling of the DEM to populate its grid cells. This means (unless you're going to do something fancy with the data) that you'll have to use a computational cell size similar to that of your DEM (1km). If you use a smaller dx in ISIS 2D, you will end up with cells near the transitions between DEM cells with potentially large changes in z across a few computational cells which will (most likely) cause ISIS 2D to become unstable.

Anand

Posted 16 February 2012 - 07:47 PM

Anand

Contributor

Validated Member

15 posts

United Kingdom

Distance between the points are 1000m on each X,Y direction.

OK... so we have a cell size now. This will be all you'll need to model the area in ISIS 2D, however, the results that ISIS 2D will not be properly georeferenced (as you do not know where the bottom-left corner of the grid is located).

You may also need to convert the spaces between values to a single space (probably best done with a simple python script).

Bear in mind that ISIS 2D will do a nearest neighbour sampling of the DEM to populate its grid cells. This means (unless you're going to do something fancy with the data) that you'll have to use a computational cell size similar to that of your DEM (1km). If you use a smaller dx in ISIS 2D, you will end up with cells near the transitions between DEM cells with potentially large changes in z across a few computational cells which will (most likely) cause ISIS 2D to become unstable.